Channel Detection Scan (channels 2-6)

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NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

ebo wrote: Tue Oct 06, 2020 10:20 am The answer that should satisfy everyone is to make the scanning range a user option. 2-51 or even 2-69 could be the default but let the users who are annoyed by the time it takes change the range to 2-36 or 8-23 or whatever is best for them.
Yup. It is extremely unlikely that my device will ever need to scan anything outside the official allocated TV channel range of 2-36. Probably more likely that I could jump over the moon. Probably similar for the vast majority of units in the U.S. and Mexico. And soon to be Canada. I was actually surprised that Mexico seems to been further along then Canada with regard to TV frequency spectrum allocation being channels 2-36. Not sure about conversion to digital, but every channel I did pull up details on was digital. So maybe they are with that too.

If Canada would get with it and stop lagging behind all North America could be channels 2-36 digital. Instead of dragging this piecemeal nonsense out as long a possible. Maybe manufactures needed some place to dump their U.S and Mexico incompatible TV's.

Choices. I like choices.

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

The repack phases only applied to Full Power and Class A stations. There are still numerous licensed LPTV stations and translators in the 38-51 range in the USA, these can be anything from so-called "useless" channels like shopping/religious, to very popular diginets like Cozi that for various reasons couldn't get clearance on a full power station in a given market, and for people in an area served by a translator, it could be their only way of picking up a big 5 network over the air. (i.e. Ukiah California where translators for the major San Francisco stations are currently in the 38-51 range) Because of the limited availability of tower crews and equipment, LPTV and Translators were not included as part of the repack phases, the majority of them now have construction permits for new frequencies in the 2-36 range, but many don't expire until 2022-2023, and depending on how bad the crew backlog still is by then, those expirations can be extended. Some of them are still analog too since the digital transition was only required for Full Power stations, but their new post-repack facilities in RF 2-36 will be digital.

As for 2-6, it was known back in 1998 that 2-6 would NOT be eliminated in the 2009 DTV conversion:
The Commission adopted a core spectrum of channels 2-51 for DTV. This decision will eliminate industry uncertainty about the status of VHF channels 2-6
Major makets like Philly have had full power VHF-lo digitals since 2009, and there were even more across the country once you start including Class A/LPTV/Translators. And it only became more populated since then, especially post-repack.

RabbitEars keeps stats of the allocated digital channels in the USA, here are the pages for the individual channel numbers so you can see a combined list of Full Power and LPTV stations:
RF 2
RF 3
RF 4
RF 5
RF 6
RF 38
RF 39
RF 40
RF 41
RF 42
RF 43
RF 44
RF 45
RF 46
RF 47
RF 48
RF 49
RF 50
RF 51

Also I just looked up your DMA Portland, it has a LPTV station KPWC-LD that will return to air on RF 6 after it was displaced from RF 24 by KATU, and there's a currently silent repeater of KRCW that's licensed for RF 5. While you may personally be out of range of these LPTV signals, they still count as part of your DMA.

wb6lzv
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Re: Channel Detection Scan (channels 2-6)

Post by wb6lzv »

I too would support having the channel scan limits be user-defined with the default being ALL. I have 2 HDHomeRuns (HDHR-US and HDHR5-4US). The HDHR5-4US is connected to a Plex Media Server and I continuously scan the tuner ports on the HDHR-US and upload the results to the RabbitEars Live Bandscan server. Scanning channels above 36 and processing the results to RabbitEars adds another minute or so that could otherwise be used to look for signals of interest (e.g. DX). It's not a huge deal, and would be a more of a "nice to have". I know my usage is in the minority. Here are my live bandscans. I have different antennas connected to the tuner ports on the HDHR-US.

https://m.rabbitears.info/index.php?req ... it=&auto=Y

https://m.rabbitears.info/index.php?req ... it=&auto=Y

tmm1
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Re: Channel Detection Scan (channels 2-6)

Post by tmm1 »

If you're using hdhomerun_config then you can simply modify the frequency ranges to suit your needs: https://github.com/Silicondust/libhdhom ... nels.c#L93

wb6lzv
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Re: Channel Detection Scan (channels 2-6)

Post by wb6lzv »

Yes... I am calling hdhomerun_config from a Python script on a Linux box. Thanks for the tip. I didn't create the original script and I'm not proficient in Python... so I'll need to digest this a little more to effectively incorporate it.

Cheers!
Craig

wb6lzv
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Re: Channel Detection Scan (channels 2-6)

Post by wb6lzv »

Let me see if I get this right. All I should need to do is re-compile hdhomerun_config for my OS with the following changes to the hdhomerun_channels.c file:

/* US antenna channels. */
static const struct hdhomerun_channelmap_range_t hdhomerun_channelmap_range_us_bcast[] = {
{ 2, 4, 57000000, 6000000},
{ 5, 6, 79000000, 6000000},
{ 7, 13, 177000000, 6000000},
{ 14, 36, 473000000, 6000000},
{ 0, 0, 0, 0}
};

In this case nothing will change with my Python script, except the channel scans will stop at 36?

wb6lzv
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Re: Channel Detection Scan (channels 2-6)

Post by wb6lzv »

Well... I answered my own question! It works perfectly, and it was so simple! Again, thank you tmm1 for the tip.

Cheers,
Craig

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Installing this LTE filter reduces the scan time on chs. 36-69 by 32 seconds (from 44 to 12 seconds; total scan time from 2:15 to 1:30).

This LTE filter blocks 600-2000 MHz (channels 36 and up).

https://www.channelmaster.com/TV_Antenn ... m-3201.htm

As a bonus it also reduces the WMC channel scan to 20 seconds for chs. 36-69.

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

Just a warning before anyone blindly buys that. They now have a newer model that starts at 610 MHz (RF 37) since their original 600 MHz model cuts out RF 36 and the top 2 MHz of RF 35, which causes problems for about 80% of the country. (i.e. in NYC WNBC is on RF 35 and WCBS is on RF 36, while portions of the Portland DMA will have several LPTV stations on RF 35 and RF 36 when everything is done)

Buying it from the Channel Master site should get you the newer model, but a lot of 3rd party retailers still have the 600 MHz model. So if anyone does end up getting the 600 MHz model, they might want to do research at RabbitEars first to check if any channels will be using RF 35 or RF 36 and contact Channel Master to see if they can get an exchange for the 610 MHz model. They should also check their market listing to make sure they don't still have any stations on RF 38-51 in their area since LPTV stations and translators were not assigned repack phases.


As for Windows Media Center, I have to double check if it affects the scan, but there are registry settings where changing the "Max Physical Frequency" might narrow the RF search:
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\TV\Tuning Spaces\ATSC"
"HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Multimedia\TV\Tuning Spaces\ATSC"

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Thanks for the WMC channel range registry tweaks.
Of note for them is:
1) Need to restart WMC and run "Set Up TV Signal" to pick up the change. Simply running a "Scan for More Channels" doesn't pick up the changed ranges.
2) Changing the "Min Physical Channel" to something other than the default of 2 breaks the channel scan. It scans for channel 2 and then stops.

Windows 8.1

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

NOYB wrote: Thu Nov 05, 2020 8:18 pm2) Changing the "Min Physical Channel" to something other than the default of 2 breaks the channel scan. It scans for channel 2 and then stops.
Which is really strange because Windows Media Center's developers coded the scan function to only scan UHF, even though by the time Vista TV pack came out in 2008, it was already known that nearly every DMA would have at least one channel in the VHF band after 2009, and there were numerous markets that already had VHF digitals during the transition. Of course this didn't become a major issue until a decade later when the repack began and they discontinued the guide data that would have automatically taken care of the RF number changes.

There might be another registry setting in the Software/Microsoft/Media Center or Software/Microsoft/Windows/Media Center under MACHINE or USER you can apply it to so you can do it without reruning Set Up TV Signal, but its path is specific to a randomly generated guid for your tuner.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

kyl416 wrote: Thu Nov 05, 2020 9:09 pm
NOYB wrote: Thu Nov 05, 2020 8:18 pm2) Changing the "Min Physical Channel" to something other than the default of 2 breaks the channel scan. It scans for channel 2 and then stops.
Which is really strange because Windows Media Center's developers coded the scan function to only scan UHF, ...
From what I understand scanning VHF was added in Windows 8.x.
I tried Min Physical Channel with 6, 7, and 14. They all did the same thing; scan ch. 2 and then stop.
Had to set it back to 2 for it to work.

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Not that it matters for me. But where do you see info on a new CM LTE filter with the block range starting at 610 MHz?
I've seen older ones that start at 700 MHz at Walmart online (at least that is what the label on the device says; who knows what would actually ship). That would be good for those in markets with LP translators still operating up there.
The Channel Master store shows the 600 MHz version (both the device image label and the tech specs).

kyl416
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Re: Channel Detection Scan (channels 2-6)

Post by kyl416 »

The Tech Specs on the Channel Master page you linked to now say it starts at 610 MHz, but the pictures still show the 600 MHz model.
"Electrical Specifications
Frequencies Pass 5 - 609 MHz
Frequencies Block 610 - 2000 MHz"

NOYB
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Re: Channel Detection Scan (channels 2-6)

Post by NOYB »

Either I missed that or they changed the tech spec page in the last week. But either way I'm good with the 600 MHz (that's what the label on the device says anyway).

I've read that if 84 MHz or more was recovered from the auction that channel 36 was going to be made a guard band for channel 37. Making both adjacent channels to 37 (36 & 38) guard bands. I've also read some things about protecting ch 36 (maybe 35 too) for some communications and medical equipment. I'm skeptical that there will be new allocations for TV broadcast in this area on ch. 36 and probably not ch. 35 either. Those already there in a crowded market perhaps would be grandfathered in.

Ordered mine a week ago on Amazon. But it is sold and shipped by Channel Master from Chandler AZ.
Chose to use buy through Amazon because the payment and shipping info is already there.

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